Shock absorber



SHOCK ABSORBER Filed Aug. 15, 1934 INVENTOR EDWIN F- ROSSMAN 04 I l- MW ATTORNEYS Patented Sept. 22, 1936 PATENT OFFICE SHOCK ABSORBER Edwin F. Rossman, Dayton, Ohio, assignor to General Motors Corporation, Detroit, Mich., a corporation of Delaware Application August 15,

14 Claims.

This invention relates to improvements in hydraulic shock absorbers adapted to control relative movements between the frame and axle of a vehicle, and particularly to the type ofshock absorber capable of being adjusted automatically in accordance with the nature of the roadbed over which the vehicle is being operated.

It is among the objects of the present invention to provide a hydraulic shock absorber of the character aforedescribed with a, manually adjustable means whereby the shock absorber may be adjusted to vary its control of the relative movements between the frame and axle of a vehicle in accordance with the desires of the operator.

In the preferred embodiment of the present invention this object is attained by providing the hydraulic shock absorber having means for circulating a fluid with pressure actuated means for controlling said circulation and with means actuated by an inertia mass for controlling the pressure actuated means in accordance with accelerations in the movements of the shockabsorber in certain directions. The shockabsorber is also provided with a check valve having manually adjustable means accessible from outside the shock absorber for so adjusting said check valve that its restriction to the flow of fluid established by the pressure actuated means may be varied to alter the effective control of the inertia'mass.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawing wherein a preferred embodiment of the present invention is clearly shown.

In the drawing: J I

Figure 1 is a fragmentary side view of the vehicle chassis, with wheels omitted, a shock absorber equipped with the present invention being shown applied thereto.

Figure 2 is a fragmentary sectional view showing the various elements of the shockabsorber and their mechanical and fluid connections.

Figure 3 is a fragmentary sectional view showing a modified form of the manual adjustment.

Referring to the drawing, the numeral 20. designates the frame of the vehicle which is supported upon the vehicle axle 2| by springs 22, only one of which is shown.

The shock absorber designated as a whole by the numeral 23 comprises a casing 24 adapted to be secured to the frame of the vehicle in any suitable manner; this casing 24 provides a fluid reservoir 25 and a cylinder 25. As shown in Figure 2, one end of the cylinder 26 is closed by an integral wall 21, the other open end thread- 1934, Serial No. 739,965

edly receiving a cylinder head cap 28, said cylinder head having a gasket 29 to prevent leaks at this end of the shock absorber.

A piston 30 is slidably carried within the cylinder 26. Said piston comprises two oppositely disposed piston heads 3| and 32, the former forming the "spring compression control chamber 33 at one end of the cylinder, the latter forming the spring rebound control chamber 34 atv the opposite end of the cylinder. A central space 35 in the piston, provided between the two heads 3| and 32, receives the free end of the shock absorber operating cam 36, this cam'engaging wear pieces 31 secured to the respective piston heads; This shock absorber operating cam 351s attached to the operating shaft 38 journaled transversely in the housing 24. One end of this shaft 38 extends outside the shock absorber casing and has the shock absorber operating arm 40 attached thereto. The free end of this arm is swivelly secured to one end of a link 4| the opposite end of said link being swivelly anchored to the axle 2| by the clamping member 42. From the aforegoing it may be seen that inresponse to the movement of the axle 2| toward the frame 20 the mechanical connections between the said axle and piston 30 will move the piston toward the left as regards Figure 2, while, as the axle 2| moves away from frame 20, said mechanical connections will move the piston 30 toward the right. Both piston head portions 3| and 32 have valved passages providing for controlled fluid flows between chambers 33 and 34 and the reservoir 25. Inasmuch as the valves in each piston head are of similar constructions and for the sake of brevity only one will be described detailedly.

Referring to the piston head portion 3| as shown in Figure 2, the numeral designates the passage through it provided for the transfer of fluid between the chamber 33 and the reservoir 25. In this passage 45 there is provided a sharp edge annular valve-seat 46 which is engaged by the intake valve 41 whose body portion 48 is of tubular construction. Spring 49, interposed between said valve 41 and a ring 50 seated in a groove, in the passage 45 of the piston head, normally yieldably maintains the valve 41 in en gagement with the valve seat 46. The pressure release valve-stem 5| is slidably supported in the tubular body portion 48 of the intake valve. This 50 stem has the valve 52 secured at its one end, said valve being yieldably maintained in engagement with the end surface of the intake valve 41 by a spring 53, interposed between the intake valve 4'! andan abutment collar 54 attached to the outer 55 is adapted to establish a substantial free floweofp-u fluid into its respective displacement chamber response to the reverse movement the device is adapted to establish a restricted flow oi tfluid- How-'2 from its respective displacement chamber. ever, the restricted flow of fluid will notbe established until a predetermined high fluidpressur'e isrbuilt up within the respective displacerne'ntv 7 chamber. The other fluid flow controldevices to 'be described' provide for fluid flows from saiddisplacement chambers at lower pressures and before the fluid flow controldevices. in the piston heads become eifective, v

As shown in Figure 2, 'the casing 2 of the shock absorber hasan extension casing 30 attached thereto, said extension casing being threadedly secured to the casing Z l. Whensecured together these two casing portions provide a chamber Bl which'isin communication with there'servoir 25.through an opening 52 in the "casing portion 24'; The casing portion 63 has a pivot. pin '63" which pivotally supportsan arm vor lever 64, the one end of Whichis attached to an inertia weightelement 65. On] each side ofj'the pivot pin 63', armor lever 64 has a contact block attached thereto, .one of ,these being designated by the numeral 66, the other by the numeral {51. A springfl68 interposedbetween' the vcasing portion 6!] and the pivoted lever 64 resiliently sfupportsthe weight65 in proper suspended position within the chamber 60.

A recess havingtwo chamber portions 75 and ll, of different diameters, is provided in the casing portion 60."The outer end of the recess chamber 'll) is interiorly thread-ed toreceive" the plug T2. The shoulder l3, formed between the two chambers l0 and H, provides an abutment engaged by thegvalve seat member which has ajcentral tubular portion providing the annular sharpedged valve-seat. i4. A spring l5, interposed between the plug. 12 and valve-seat l4; maintains saidvalve-sea't against the abutment shoulder "l3. A conduit 15 provides communication between the 7 spring compression control chamber 33an'd the chamber 70. Another recess ll opening'into the chamber 6 l; and in coaxial alignment with recess chambers fill and?! is in communication with the chamber "l'l through a passage 18 which is of '82; formed on the valve-stem l9 and slidably supported within recess ll, and the screw plug 83 'threadedly received by the outer open end of recess 'l 'l. Itwill be noted that valve-stem l9 is'hollow, one, end opening intothe recess ll above the piston 82, the other end being in communication with chamber ll throughthe orifice 84' provided in the side wall of the'valve-stem l9.

The chambe'rfll into which the orificedrend of casing portion 60. in response to one movement of the piston'iand in 'lBl interposedbetween the piston head the valve-stem 19 extends has a passage 35 leading therefrom which passage communicates with a recess 86 formed in the housing casing portion 66. Communication between the passage 85 and the recess 86 is normally shut ofi by the valve Bl urged into normal position by spring 88, one end of which engages valve 81, the other, an adjustable abutment member 89, slidably supported within the recess 86. This abutment member 89 rests upon an extension 9B of a screw threaded actuator 9l which threadedly engages a recess 92 formed in a block 93 removably attached to the This adjustable actuator 9i hasa stem portion 94 extending through any suitable packing 95 to the exterior of the shock absorber so as to be accessible from the outside of theshock absorber. Recess 85 and more particularlythe portion of recess 86 between the 'valve 87 and the adjustable abutment member 89 is. in'communication with the spring rebound control chamber 34 through the conduit 93 and a'passage 91' with which said conduit communicates;

' The recess l1 and particularly the chamber therein between piston 82 and the screw plug 83 has a passage I00 leading therefrom which communicates with passage lGl one end of passage llll terminating in a cross passage H12 capable of discharging fluid into the chamber Ell. A valve I33 is normally urged by gravity to shut on com- I munication between passage llil and the cross passage l62, this valve )3 aligning with the contact block 66 mounted on the pivot lever 64.

The fluid flow control mechanism just described is adapted toregulate fluid flow from chamber 33 to chamber 3 5.3 A similar mechanism is provided to control fluid flow from chamber 34 tochamber 33. In this mechanism there is provided a recess having different diameter chambers I and Ill. The outer end of recess ill) is interiorly threaded to receive the screw-plug H2.

The shoulder l'l3 between the two different diameter recess portions l'a'll and ill is engaged by an annular flange of tubular valve-seat PM Which is urged into engagement with said shoulder E13 by the spring l'l5 interposed between the valve- 117.. Like the" other valve 79, valve l'l9 has an orifice I84 which provides communication between the recess chamber rl'll and the interior of the tubular valve-stem llS which in turn dis charges into'the recess lll above the piston H82.

Chamber l'll has a passage I85 leading therefrom said passage opening into the recess l36 formed in the housing portion 55. Normally fluid is prevented from flowing from passage 35 into chamber l8'i by the valve l8? which is yieldably urged into said communication shut-01f position by a spring I88. interposed between said valve l81 andan adjustable abutment member i859 slidably carried within the recess lfifi. Like abutment member 89, this abutment member 'l89 rests upon the inner stem portion I98 of the adjustable actuator whose threaded portion lSl threadedly engagesthe recess I92 in block 93 and whose stem s The H cessible for adjusting purposes. has a passage 200 leading therefrom which communicates with passage 20I, one end of which portion I94 extends through a packing I95 to theoutside of the shockiabsorber so as to be ac- The recess I11 .between the passage 20I and the cross passage 202, this valve 203 coaxially aligning with the contact block 61 carried on the pivoted lever 04.

In order that-no fluid may be trapped beneath the pistons 82 and I82 to prevent downward movement, a passage 205 connects the recesses 11 and I11 beneath said pistons 82 and I82 so that when one piston moves downwardly any fluid beneath it may be discharged into the space beneath the other piston. I

A conduit 208 connects chamber I1.0 with the recess 80 and a similar conduit 201 connects chamber 10 with the recess I86.

In Figure 2 the drawing illustrates two separate and distinct adjustable actuators for the spring abutment members 89 and IE9 respectively. In the modified form shown in Figure 3 a single actuator is provided, operation of which will adjust both abutment members 89 and H39 simultaneously. In this structure a stem 2|0 engages the abutment 89, a similar stem 2| I engaging the abutment member I89. These stems are secured to a common bridging member 2| 2 which rests Aside from exactly like that shown in Figure 2.

The fluid flowcontrol mechanism just described operates as follows: When the piston 30 is moved toward the left in response to the approach of the axle 2| toward the frame 20 a pressure will be exerted upon the fluid within the chamber 33. Before this pressure reaches a value suflicient to move valve 52 from engagement with valve 41 fluid will be forced from chamber 33 through conduit 16 into the chamber 10. Fluid pressure acting in chamber will, when attaining a proper value, move valve-stem 18 against the effort of its spring 8|, out of engagement with valve-seat 14 to permit fluid to flow from chamber 10 through valve-seat 14'into the chamber 1|. From chamber 1| this fluid will flow through passage 85 against valve 81, which being provided with a comparative light spring, will move from its seat to permit the fluid to flow from the passage 85 into the chamber 80. From this chamber the fluid will flow into conduit 90 and its communicating passage 01 into the spring rebound control chamber 34. The restriction to fluid flow from passage 85 into chamber 86, which restriction is offered by the Valve 81, creates a pressure within chamber 1| and causes fluid to flow from said chamber through the orifice 84 in tubular valve 18 into the recess 11 above the piston 82. From chamber I1 fluid will flow through passages I00 and till, the fluid pressure lifting valve I03 against the effect of gravity and discharging through cross passage I02 into the chamber 6| If at this time the acceleration in the downward movement of the body-carrying frame'of the vehicle reaches a predetermined value, relative movement between the shock absorber casing 24' and the weight 05 obtains. This movement of the weight 65 will cause arm 64 to rotate counterclockwise about its pivot pin 03 and consequently contact block 66 will. engage valve I03 and urge it into closer proximity to the seat provided at the outer, open end of passage |0I thereby increasing the restriction to the flow of fluid from said passage.

This increase of restriction to the flow from passage |0I will create a pressure within chamber- I11 above the piston 82 and due to the factrthat the piston 82 is of comparatively large size, the

eifect of the substantially low pressure will be multiplied, thereby moving the closed end 80 of the stem portion 19 to more closely approach to valve-seat 14 against the effect of thecomparatively high fluid pressure and thus increasing the restriction to the high pressure flow of fluid from I chamber 10 into the chamber'II which may be termed the main flow. Increasingly restricting the main flow will naturally result in increased resistance offered by the shock absorber for the restriction to the main flow will naturally resist the movement of piston 30 toward the left, said piston being mechanically connected with the= axle 2| of the vehicle. Thus it may be seen that the resistance offered by the shock absorber is proportionate to the acceleration in the movement of the frame relatively to the axle. .The fluid flow control device just described may be termed a multiplying valve because the effect of a low fluid pressure is multiplied to control a comparatively high pressure flow, This high fluid pressure acting against the surface 80 of the valve-stem 19 moves said stem and its enlarged piston portion 82 against the effect of spring 8| to permit a fluid flow through valve-seat M and passage. 85 which flow is impeded by the static valve 81. This impedance to flow of fluid through passage 85 causes a back pressure of comparatively lesser value than the fluid pressure on valve-stem surface 80, to be built up in chamber II and consequently recess 11 which is in communication with chamber II by the orifice face 80 of valve-stem 19, actuates said piston and stem against said high fluid pressure to restrict fluid flow past valve-stem 19. Thus the effect of a lower fluid pressure is multiplied to overcome the effect of a much higher fluid pressure and the piston portion 82 together with inertia mass actuated valve I03 and valve stem 10 constitutes what is termed a multiplying valve.

On'the other hand supposing the piston 30 moves toward the right in response to separate movements between the axle and frame of the vehicle, fluid will be forced from chamber 34 through passage 91 and conduit 90 into the recess 86. From here the fluid will flow through conduit 206 into the recess I10 and as it urges the closed end of valve I80 of valve-stem I19 from engagement with valve-seat I'M against the effect of spring ,I8I, a flow is established from chamber I10 into the chamber I'II. Leaving chamber III the fluid will flow through passage I 85 against valve l81 moving said valve and permitting fluid to flow into the recess I00. From here the fluid will flow into the spring compression control chamber 33 via the passage 201, recess 10 and the conduit 16. Valve I81 in restricting this flow creates a pressure in the chamber III which causes fluid to flow into the valve-stem I19 and discharge 'into the chamber-ill above piston I82. From this recess I'll fluid flows through passage 25H against valve 203 lifting said valve against gravity to permit fluid to discharge from passage 20I through cross passage 202 into the chamber BI. If under these circumstances the upward movement of the frame 20 be accelerated to a certain'degre-e, relative movement between the weight 65 and the shock absorber. casing obtains causing the weight to I82 to be moved downwardly sothat the closed end I86 of the valve-stem Ilswill more closely approach the valve-seat l'l l thus restricting the main flow from the recess I is in the chamber I II. This restriction to the main flowwill in crease the resistance of the shock absorber to the separating movement of the frame and axle and consequently will resist the upward movement of the body-carrying member 20. I

It may clearly be seen that the pressure buildup within chambers H and HI respectively is dependent upon the restriction offered by valves 8'! and'I8'I. At a certain spring load these valves will restrict the main'fluid flow to a certain degree and consequently a certain pressure is built up within the respective chambers ii and iii. If this spring load upon/these valves be increased their restriction to the'respective fluid flows will likewise be increased and consequently pressure build-up in the respective chambers II and Ill will naturally be increased. Increasing'the fluid pressures within the chambers ii and HI will require a greater effort on the part of the weight 65 to' restrict fluid flow from recesses ill and Ill respectively which are in communication with said chambers.

- cured to actuators 9 and I94 respectively whereby, adjustments may bemade from the outside of the shock absorber, the spring load on valves 87 and i8? may be varied. If the operator finds that the control of the downward accelerations of the body-carrying frame is not sufficient or more explicitly, if he desires a greater resistance to be offered to such downward movement of the body- -carrying frame 26, he operates the actuator 94 so that it will reduce the load of the spring '88 upon the valve 87. This naturally reduces the restriction offered by the valve Bl to the main fluid flow and consequently'the pressure in chamber '!I will likewise be reduced. The pressure in chamber II being reduced, a lesser effort on the part of weight 65 is required to restrict fluid flow from chamber IT by actuation of the valve I03 and thus lesser accelerations downwardly of the body will result in the weight actuated mechanism becoming fully efiective. If the upward accelerations of the body-carrying frame require greater resistance then the operator actuates the actuator I94 in a similar manner thus reducing the pressure within the chamber Ill and naturally requiring less effort on the part of the weight 65 to move the valve 283 to restrict fluid flow from chamber .II'I which is in communication with chamber I'II On the other hand if accelerated movements of the body-carrying frame 20 require a lesser resistance in the opinion of the operator either one or both of the actuators 94 or I94 may be actuated to increase the spring load upon the valves 81 and I8! whereby a greater pressure will be built up within chamber II and I "II and thus requiring a greater efiort on the part of the weight to build up a sufficient pressure within chamber TI or IT! to effect adjustment of the respective valves.

In the modified form a single actuator is provided whereby both valves 81 and I8! have their spring loads varied concurrently and in this structure it is not possible as in the other structure separately to adjust the spring load of these respective valves.

From the foregoing description it may readily be seen that applicants improve-d hydraulic shock absorber comprises means for circulating a fluid, which means comprises pistons SI and 32, forming displacement chambers 33 and 34 which are inter-connected by ducts I6 and 96 and associate passages and valve chambers. This includes also pressure actuated means for controlling said circulation, which means comprises valves 19 and i re, these valves being adapted to be actuated by fluid pressure to permit fluid flows between the displacement chambers 33 and 34. It also comprises means actuated by an inertia mass for controlling the aforesaid pressure actuated means, the inertia mass actuated means being the valves 1G3 and 293, adapted, to be actuated to restrict fluid flow from the respective pressure actuated means in accordance with the operation of the inertia weight actuated lever 64. Applicants hydraulic shock absorber also includes a manually adjustable check valve adapted to restrict the flow of fluid established by the pressure actuated --means forvarying the eifective control of the inertia mass actuated means, the check valves being designated by the numerals 8! and I81, said valves being urged normally to close their respective fluid circulation by springs 88 and I88 respectively, the pressure of these springs upon their respective valves being adapted to be varied by the actuation of. the manually adjustable means 94 and l 94 accessible from outside the shock absorber. Changing the pressure of the springs upon their respective valves will vary the restriction to the flow of fluid through the passages normally closed by these valves, thus resulting in a variation of the effective control of the inertia mass actuated means.

From the afcregoing brief description of applicants improved shock absorber it may readily be seen that applicant has provided a hydraulic shock absorber capable of adjusting itself automatically in response to and proportionately with accelerations in the upwardand downward movements of the body-carrying frame 20 whereby the resistance to the relative movements between said frame and the axle of the vehicle is varied in accordance with the movement of the body-carrying frame. He has also provided means within easy reach of the operator of the vehicle, which may be moved by the operator while the vehicle is in motion to adjust or change the effective resistance oifered by the shock absorber. If the operator feels that more resistance is required he can move the actuators to adjust the shock absorber so that it will provide the desired resistance. If on the other hand, the operator feels that too stiff a ride is being had, he may remove the actuator to soften the operation of the shock absorber in that it will offer less resistance to relative movements between ,the body'-carrying frame and the axle. Two'forms of actuators are provided one in which the entire shockabso'rber is adjusted by a single operation the other form provides a separate adjustment to varythe con?v trol of the upward movement and a separate ad; justment to vary the controlof the downward of the body-carrying frame of the eans. l;

'7. A hydraulic shock'absorber having, mean'sfor movement ,vehicle.

. claims which follow.

What is claimed is as follows:

1. .A hydraulic shock absorber having means for circulating'a'fluid; means for regulating said fluid circulation proportionately with the accelerations in the movements of the shock absorber; separate means adapted to restrict said fluid circulation to render the said circulation regulating means eife-ctive; and manually operated means for adjusting said separate means to vary its restriction to fluid circulation whereby the regulating effect of the first-mentioned means is altered.

2. A hydraulic shock absorber having means for circulating a fluid; means for regulating said fluid circulation; inertia weight controlled means for adjusting the aforementioned means to vary its regulation of the fluid circulation; a constantly effective spring loaded check-valve for restricting the regulated flow of fluid to render the Weight controlled means effectiveqand manually operated means for adjusting the spring load upon the check-valve to vary its restriction to fluid flow whereby the adjusting effects of the weight controlled means are varied.

3. A hydraulic shock absorber having means for circulating a fluid; pressure actuated means for controlling said circulation; means actuated by an inertia mass for controlling the aforementioned means; and a manually adjustable checkvalve adapted to restrict the flow of fluid established by the pressure-actuated means for varying the effective control of the inertia massactuated means.

4. A hydraulic shock absorber having means for circulating a fluid; means for regulating said fluid circulation; an inertia mass actuated means for adjusting the aforesaid means in response to and proportionately with accelerations in the vertical movements of the shock absorber; and a manually adjustable check-valve adapted to restrict the fluid circulation to render the inertia mass actuated means operative.

5. A hydraulic shock absorber having means for circulating a fluid; a valve normally preventing fluid circulation but adapted to be actuated by fluid pressure to permit fluid flow, said valve having means providing for a flow of fluid through the valve after it is actuated by fluid pressure; a check-valve for restricting the fluid circulation to build up a predetermined pressure in the flow of fluid through the first-mentioned valve; control means actuated by an inertia weight for regulating the flow of fluid through said valve to effect adjustment of said valve; and manually operable means for adjusting the check-valve to vary the pressure of the fluid flow through the first-mentioned valve whereby to alter its adjustments by the inertia weight actuated control means.

6. A hydraulic shock absorber having means for circulating a fluid; means adapted to be actuated by fluid pressure to permit said fluid circulation;

While the embodiment of the present invention as herein disclosed, constitutes a preferredform;" it is to be understood thatother forms mightbe inertia mass controlledmeans for adjusting said aforementioned means tovary its control of the fluid circulation; means, for restrictingithe circulationof "fluid to "renderfthe inertia mass controlled means effective; and manually operable means; for adjusting said fluid flow restricting means to varythe'adjustment of the first-mentioned means by the inertia mass controlled adjusting the firstmentioned springloaded valve inresponse to and proportionately "with ac-" celerations in the movements of the shock absorber; and means adapted to be operated manually for adjusting the second spring loaded valve to vary the effects of the means acting in response to accelerations in the movements of the shock absorber.

8. A hydraulic shock basorber having means for circulating a fluid; a valve adapted to provide for a main and a secondary flow of fluid in response to a predetermined fluid pressure; a check-valve for restricting the main fluid flow to raise the pressure of the secondary flow to a predetermined degree; means acting in response to accelerations in the movements of the shock absorber for regulating said secondary flow to adjust the first-mentioned valve; and manually operable means for adjusting the check-valve to vary its restriction to the main fluid flow, whereby the adjustment of the first valve by the means acting in response to acceleration will be varied. i

9. A hydraulic shock absorber adapted to circulate a fluid; two valves adapted to restrict said fluid circulation, one of them being spring loaded; an inertia controlled valve for regulating the other of said two valves; and manual means, accessible from outside the shock absorber for adjusting the spring loaded valve.

10. A hydraulic shock absorber having means for circulating a fluid; an inertia weight; a pressure actuated valve adapted to be controlled by the inertia weight for variably restricting said fluid circulation; a spring loaded valve restricting the fluid circulation to render the inertia weight control of said first mentioned valve effective; and manually operated means, accessible from outside the shock absorber for adjusting the spring loaded valve.

11. A hydraulic shock absorber having means for circulating a fluid; pressure actuated means for controlling said fluid circulation; a spring loaded valve adapted to restrict said fluid circulation to provide a diverted fluid flow; an inertia mass controlled valve for restricting said diverted flow of fluid in response to accelerations in the movements of the shock absorber; means actuated by the said restricted diverted flow for increasing the controlling effect of the pressure actuated means; and manually operated means accessible from outside the shock absorber for adjusting the spring loaded valve to vary its restriction to the fluid circulation.

12. A shock absorber for vehicles of the type having a sprung and unsprung mass comprising, in combination, a cylinder and a piston actuated by the relative movements of the said masses for subjecting a fluid to pressure, means including a multiplying valve and a control mass for determining the degree of pressure to which the fluid is Subjected; a check-valve for renderings said meanseifective; and"manually operated" means, accessible from outside the shock absorbenadapted to adjust said check valve to 5 vary the efiect of said first mentioned means."

; 13. A hydraulic shockabsorber having a spring loaded valve for determining, the degree of shock I j absorberresistance; means adapted" to be actu ated by fluid pressure to' adjust said valve; an" 10 inertia weight controlled device adapted to render the aforementioned means 'efiective to adjust the valve for increasing the, resistance of the shock absorber in' responseto accelerations in the movements of the shock absorber; 'a'sp'rling -loa'ded 15 ,check valve adapted to render the first mentioned means efiective; and manually adjustable means, accessible from outside the shock abexposed tdfluid pressure and aninertia mass controlled. valve for determining the fluid pressurfwithinsaid. chamber; a check valve adapted to pf'ovide'pressure to render the first mentioned valve effective to restrict fluid flow; and means accessible from outside the shock absorber for adjusting said check. valve.

EDWIN F. ROSSMAN. 

